TY - JOUR T1 - Cnidarian hair cell development illuminates an ancient role for the class IV POU transcription factor in defining mechanoreceptor identity JF - bioRxiv DO - 10.1101/2021.10.12.464036 SP - 2021.10.12.464036 AU - Ethan Ozment AU - Arianna N. Tamvacakis AU - Jianhong Zhou AU - Pablo Yamild Rosiles-Loeza AU - Esteban Elías Escobar-Hernandez AU - Selene L. Fernandez-Valverde AU - Nagayasu Nakanishi Y1 - 2021/01/01 UR - http://biorxiv.org/content/early/2021/10/14/2021.10.12.464036.abstract N2 - Although specialized mechanosensory cells are found across animal phylogeny, early evolutionary histories of mechanoreceptor development remain enigmatic. Cnidaria (e.g. sea anemones and jellyfishes) is the sister group to well-studied Bilateria (e.g. flies and vertebrates), and has two mechanosensory cell types – a lineage-specific sensory-effector known as the cnidocyte, and a classical mechanosensory neuron referred to as the hair cell. While developmental genetics of cnidocytes is increasingly understood, genes essential for hair cell development are unknown. Here we show that the class IV POU homeodomain transcription factor (POU-IV) – an indispensable regulator of mechanosensory cell differentiation in Bilateria and cnidocyte differentiation in Cnidaria – controls hair cell development in the sea anemone cnidarian Nematostella vectensis. N. vectensis POU-IV is postmitotically expressed in tentacular hair cells, and is necessary for development of the apical mechanosensory apparatus, but not of neurites, in hair cells. Moreover, it binds to deeply conserved DNA recognition elements, and turns on a unique set of effector genes – including the transmembrane-receptor-encoding gene polycystin 1 – specifically in hair cells. Our results suggest that POU-IV directs differentiation of cnidarian hair cells and cnidocytes via distinct gene regulatory mechanisms, and support an evolutionarily ancient role for POU-IV in defining the mature state of mechanosensory neurons.Competing Interest StatementThe authors have declared no competing interest. ER -